FLEXURAL CAPACITY OF COMPOSITE GIRDERS : DESIGN EQUATION ACCOUNTING FOR BRIDGE HIGH PERFORMANCE STEELS

• Material Type: 博士論文
• Title: FLEXURAL CAPACITY OF COMPOSITE GIRDERS : DESIGN EQUATION ACCOUNTING FOR BRIDGE HIGH PERFORMANCE STEELS
• Author/Editor: Dang, Viet Duc
• Author Heading: Dang, Viet Duc
• Publication Date: 2013
• Publication Date (W3CDTF): 2013
• Alternative Title: 合成桁の曲げ強度 ： 橋梁用高性能鋼を考慮した設計式
• Periodical title: 博士論文（埼玉大学大学院理工学研究科（博士後期課程））
• Degree grantor/type: 埼玉大学
• Date Granted: 2013-09-20
• Date Granted (W3CDTF): 2013-09-20
• Dissertation Number: 乙第212号
• Degree Type: 博士(学術)
• Conferring No. (Dissertation): 乙第212号
• Text Language Code: eng
• Subject Heading: bridge high performance steels; local bucking strength; residual stress; initial deflection; Monte Carlo based simulation; response surface; partial safety factor; composite I-girder; web slenderness limit; ultimate flexural strength
• Target Audience: 一般
• Note (General): type:text; The steel-concrete composite girder is one of the most common supper-structural types for highway and railway bridges. In composite girders under un-shored construction method, which is very common for composite girders, first, a steel girder only resists a bending moment due to dead loads of steel and wet concrete. The local buckling of the top flange plate in the steel girder due to the initial bending moment critically dominates the flexural resistance of the composite girders in the construction state. Besides, application of bridge high performance steels SBHS500, SBHS700 and hybrid steel girders is expected to be an economical solution for composite girder bridges. Steels SBHS500 and SBHS700, with yield strengths of 500 and 700 MPa, respectively, have been standardized in 2008 in Japannese Industrial Standards (JIS). They present the advantage of high yield strength, good weldability. However, if compared to conventional (normal) steels they possess different inelastic behavior, such as almost no yield plateau, smaller ductility, and a greater yield-to-tensile strength ratio. The bending moment capacity of a composite girder largely depends on local bucking of compressive components, such as flange plates and web plates. Hence, the local buckling strength of simply supported steel plates and section classifications based on the web slenderness limits of composite girders with SBHS steels for homogeneous as well as hybrid sections are investigated in the current study.In this dissertation, a probabilistic distribution of buckling strengths for compressive plates with normal and bridge high performance steels was obtained through numerical analyses to propose nominal design strength and a corresponding safety factor. In the numerical analyses, Monte Carlo based simulation, which is combined with the response surface method, was employed to reduce exertion of finite element analyses. For each of 10 widthto- thickness parameter R values ranging from 0.4 to 1.4, a response surface of the normalized compressive strength was identified based on 114 finite element analysis results which include 4 normal and 2 high strength steel grades with different residual stresses and initial defections. The response surface is approximated as a simple algebraic function of the residual stress and the initial deflection. For the Monte Carlo based simulation in the current study, a pair of variables of residual stress and initial deflection is generated randomly in accordance with the probabilistic characteristics reported by Fukumoto and Itoh (1984). The LBS is evaluated deterministically by means of the response surface for the generated random variables. The probabilistic distribution of LBS is obtained from simulating 10,000 pairs of the random variables. The mean values obtained from results of LBS probabilistic distribution in the current study agree to those from experiments reported by Fukumoto and Itoh (1984). The obtained standard deviations of the current study exhibit about half of experimental results in a range of 0.6<R<1.2. Regarding each of 6 steel grades, the mean LBS strength of SBHS steel plates is greater than that of the normal steel plate. For R>0.55 the standard deviation of LBS regarding SBHS steel plate is lower that that of normal steel plates. Judging this behavior, the design normalized LBS strength of steel plate will attain higher value with application of SBHS steels than normal steels for R>0.55. In the range of 0.4≤R≤0.85, the variance of LBS is more sensitive with initial deflection than residual stress. Whereas in the range of R>0.9, the variance of LBS is more sensitive with residual than initial deflection. For the nominal strength set to the mean value and probabilistic distribution of LBS is the normal distribution, the partial safety factors are obtained as 1.11, 1.13, and 1.16 for non-exceedance probability of the probabilistic LBS with respect to the nominal LBS equal to 5.0, 3.0, and 1.0%, respectively.For investigation of web slenderness limits for section classifications of composite girders, the positive bending moment capacity of composite girders is examined through parametric study employing elasto-plastic finite element analyses. The section classification based on web slenderness limits for composite homogeneous and hybrid steel girders with bridge high performance steel SBHS500 are explored. Besides, the effects of the initial bending moment due to unshored construction method on the web slenderness limit are investigated. For section classification of composite hybrid girders, the yield moment, which is calculated from the yield moment of the corresponding composite homogeneous girders and hybrid factor, is an essential quantity. However, the hybrid factor specified in AASHTO was proposed without considering the initial bending moment. In the current study, the modified hybrid factor is proposed to determine the yield moment of hybrid sections from the corresponding homogeneous sections. Under the effect of different inelastic behavior of SBHS500 steel and the initial bending moment, it is shown that the compact- noncompact web slenderness limits in conventional design standards are over-conservative for both composite SBHS500 homogeneous and SBHS500-SM490Y hybrid steel girders. Many composite sections, which are classified as slender by current specifications, demonstrate sufficient flexural capacity as noncompact. The compact-noncompact web slenderness limit of composite SBHS500-SM490Y steel sections is greater than that of composite SBHS500 homogeneous steel sections. However, the noncompact-slender web slenderness limit for SBHS500-SM490Y hybrid sections is a little lower than that of SBHS500 homogeneous sections. For composite girders with non-compact sections with the initial bending moment, the proposal hybrid factors are slightly lower than those obtained from FEM analysis results, and the difference is about 5%. With considering a higher level of the initial bending moment, the hybrid factors using in AASHTO shows un-conservativeness. The investigation of section classification based on web slenderness limits of composite girders with SBHS500 steel for both homogeneous and hybrid steel girders shows that the web plate of steel girder can be designed with higher slenderness than requirements of current specifications such as AASHTO and Eurocode.; ABSTRACT ........................................................................................................................iiiACKNOWLEDGEMENTS ............................................................................................... viiTABLE OF CONTENTS.................................................................................................... ixLIST OF FIGURES ............................................................................................................ xiLIST OF TABLES ........................................................................................................... xviiCHAPTER 1......................................................................................................................... 1BACKGROUND .................................................................................................................. 11.1 Introduction of composite girder bridge .............................................................. 11.2 Design issues for composite girder bridges ......................................................... 51.2.1 Thicker steel plates and new steel grades ............................................................ 51.2.2 Allowable Stress and Limit State Design Method ............................................... 81.3 Trend of recent design methods .......................................................................... 91.3.1. Probability-based design..................................................................................... 91.3.2. Allowable stress of JSHB ................................................................................. 111.3.3. AASHTO-Load and Resistance Factor Design (LRFD).................................. 111.3.4. Eurocode-Format of partial safety factor format............................................. 121.4 Summary of issues............................................................................................ 13CHAPTER 2....................................................................................................................... 15LITERATURE REVIEW AND OBJECTIVES ............................................................... 152.1 Reviews on compressive steel plates................................................................. 152.2 Review on bending composite girder ................................................................ 212.2.1. Hybrid factor .................................................................................................... 212.2.2. Current classification of composite sections...................................................... 232.2.3. Study of Gupta et al., (2006)............................................................................. 242.3 Objectives ........................................................................................................ 26CHAPTER 3....................................................................................................................... 28STATISTICAL INFORMATION OF LBS FOR STEEL PLATES................................ 283.1. Introduction...................................................................................................... 283.2. Plates properties ............................................................................................... 303.3. Random inputs.................................................................................................. 323.4. FE steel plate model ......................................................................................... 373.5. Response surface .............................................................................................. 423.6. Results from random simulation and discussion................................................ 463.6.1. Convergence of the random simulation results.................................................. 463.6.2. Results from random simulation ....................................................................... 473.6.3. Approximate estimation of mean and variance.................................................. 553.6.4. Proposal of partial safety factor ........................................................................ 603.7. Conclusions...................................................................................................... 67CHAPTER 4....................................................................................................................... 69WEB SLENDERNESS LIMITS FOR SECTION CLASSIFICATION OF COMPOSITE GIRDERS........................................................................................................................... 694.1. Introduction...................................................................................................... 694.2. FEM simulation model of pure flexural composite girder ................................. 734.3. Proposal of hybrid factor .................................................................................. 814.4. Web slenderness limits in design of composite girders...................................... 864.5. Conclusions...................................................................................................... 95CHAPTER 5....................................................................................................................... 97CONCLUSIONS AND RECOMMENDATIONS............................................................. 975.1. Conclusion remarks .......................................................................................... 975.2. Contribution of the current study .................................................................... 1005.3. Recommendations for future research............................................................. 100REFERENCES ................................................................................................................ 102APPENDIX 1 ................................................................................................................... 106RESPONSE SURFACES................................................................................................. 106A1-1 Case 1-regarding all 6 steel grades for each R value ................................... 106A1-2 Case 2-regarding each among 6 steel grades for each R value ................... 108APPENDIX 2 ................................................................................................................... 120PROBABILISTIC INFORMATION OF LBS................................................................ 120A2-1 Case 1-regarding all 6 steel grades for each R value ..................................... 120A2-2 Case 2-regarding each steel grade for each R value ...................................... 122APPENDIX 3 ................................................................................................................... 132PROPERTIES OF COMPOSITE SECTION................................................................. 132A3-1 Yield moment.............................................................................................. 132A3-2 Plastic neutral axis and plastic moment capacity of homogeneous and hybrid section................................................................................................ 136; 主指導教員 : 奥井義昭
• DOI: 10.24561/00010299; https://doi.org/10.24561/00010299
• Persistent ID (NDL): info:ndljp/pid/8951358; https://dl.ndl.go.jp/pid/8951358
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• Collection (particular): 国立国会図書館デジタルコレクション > デジタル化資料 > 博士論文; https://dl.ndl.go.jp/collections/A00014
• Acquisition Basis: 博士論文（自動収集）
• Available (W3CDTF): 2015-03-03
• Date Accepted (W3CDTF): 2015-02-03T05:25:05+09:00
• Date Created (W3CDTF): 2014-07-16
• Format (IMT): application/pdf
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• Periodical Title (URI): http://dx.doi.org/10.24561/00010299; http://id.nii.ac.jp/1586/00010299/
• Data Provider (Database): 国立国会図書館 : 国立国会図書館デジタルコレクション; https://dl.ndl.go.jp

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2023-09-04 再収集